This invention relates to pressure jacket systems for securing a syringe in an injector head. More specifically, the invention relates to pressure jacket systems which allow front loading and removal of a syringe, and which hold the syringe securely to an injector head during injection procedures.
In the medical field, patients often are injected with fluids in procedures such as angiography. In such procedures, which require controlled injection of a large volume of fluid into a patient, a needle is used as a conduit for the fluid which is connected to the syringe by a connector tube. The syringe is mounted on a motorized injector having an injector head.
For long term compatibility with injectable fluids, syringes may be made of polypropylene with a certain minimum wall thickness. The thickness is critical as typical pressures of up to 1200 p.s.i. are used to inject the fluids into a patient. For safety and sanitary reasons, different disposable syringes are used for different fluids and different patients.
Pressure jackets are known in the art for enclosing and retaining syringes while in use. A pressure jacket serves to limit radial expansion of a syringe which may lead to bursting or to leaks of the pressurized fluid around the seals of the syringe plunger. Another function of a pressure jacket is to prevent forward motion of the syringe. For example, typically a force of 2000 pounds is required to restrain the forward motion of a 200 ml syringe with a cross-section of 1.7 in 2 at 1200 p.s.i.
Certain present pressure jackets are one piece designs, where the syringe is inserted into the jacket from the rear end of the jacket. An example of such a pressure jacket is found in U.S. Pat. No. 4,677,980, assigned to the common assignee of this application. The neck of the syringe protrudes from the front end of the pressure jacket for connection of fluid lines which lead to the patient. Because the diameter of the syringe neck is much smaller than that of the syringe barrel, it can withstand both radial and forward force.
However such an arrangement causes a problem when the syringe is removed from the pressure jacket. The neck of the syringe must pass through the present pressure jacket configurations. This requires the patient fluid path to be disconnected which presents a potential biohazard and may result in spilling fluids onto the pressure jacket. Additionally, fluid spilled during loading and purging air from the syringe may get inside the pressure jacket and require cleaning.
Thus, a pressure jacket system is needed which permits a syringe to be front loaded onto an injector head and removed from the injector head without disconnecting the patient fluid path. Further, a pressure jacket system is needed which reduces the materials required for the manufacture of the syringe.
The present invention relates to front loadable pressure jacket systems for use with injectors having an injector head with a housing and a front opening. A syringe is connected to the injector front opening to allow the flow of fluids through the syringe. A pressure jacket holds the syringe to the injector head. A piston extendible through the injector front opening imparts motive force to a plunger in the syringe to cause fluid flow.
One embodiment of the present invention is a pressure jacket having first and second jacket halves each having interior surfaces conformable to the exterior surface of the syringe. A hinge pin extends from the front face of the injector head. The first and second jacket halves are rotatably mounted on the hinge pin. The halves may be placed in an open position allowing insertion and removal of the syringe or a closed position so that the jacket surrounds the syringe.
A second embodiment of the present invention includes a pressure jacket with first and second jacket halves, where each jacket half has a front or distal end and a rear or proximal end. A hinge for rotational connection to the injector""s front face allows the first and second jacket halves to be placed in an open position, allowing insertion and removal of the syringe, and a closed position such that the jacket substantially surrounds the syringe. A locking ring is disposed around the first and second jacket halves. The locking ring is placed in a position over the front ends of the first and second jacket halves when in the closed position and the ring is placed in a position near the proximal ends of the jacket halves when in the open position.
A third embodiment of the present invention includes a pressure jacket which has a hollow cylinder portion with an open distal end and a rear end coupled to the injector head. The cylinder has at least one locking finger having front and rear ends, and a pivot axis disposed near the rear end. The pivot axis is connected to the open distal end of the cylinder. The locking finger is pivotable to a closed position such that the front end of the finger acts to hold the syringe within the cylinder. The finger is pivotable to an open position to allow the insertion or removal of the syringe.
A fourth embodiment of the present invention includes a pressure jacket having a jacket cylinder with an open front end and a rear end coupled to the injector head. A first tie rod has a rear end attached to the injector head and a front end which is attached to a first front plate. The first front plate is pivotable between a closed position for holding the syringe within the jacket cylinder and an open position for allowing the insertion or removal of the syringe. A second tie rod likewise has a rear end attached to the injector head and a front end attached to a second front plate. The second front plate is pivotable between a closed position for holding the syringe within the jacket cylinder, and an open position for allowing the insertion or removal of the syringe.
A fifth embodiment of the present invention includes a pressure jacket with a jacket cylinder having an open front end and a rear end coupled to the injector head. A first pivot is coupled to the injector head and a first tie rod is attached to the first pivot. A second pivot is coupled to the injector head and a second tie rod is attached to the second pivot. A front retaining plate joining the front ends of the tie rods allows the retaining plate to be pivotable between a closed position for holding the syringe within the jacket cylinder and an open position to allow the insertion or removal of the syringe from the jacket cylinder.
A sixth embodiment of the present invention includes a pressure jacket which has a jacket cylinder formed around a longitudinal axis and having an open front end and a rear end. The jacket cylinder is transversely pivoted to the front face of the housing to allow the cylinder jacket to be pivoted between a closed position and an open position. An arm having a rear end affixed to the injector head is attached to a retaining member. The retaining member retains the syringe in the jacket cylinder when the jacket cylinder is in a closed position. The jacket permits the loading or removal of the syringe when the jacket cylinder is in an open position.
A seventh embodiment of the present invention includes a pressure jacket which has a slidable canopy retractable within the injector head. An arm having a rear end is coupled to the injector head. The front end of the arm is coupled to a retaining member and retains the syringe. The canopy slides to a closed position to retain the syringe and slides to an open position to allow the insertion or removal of the syringe.